App
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Appendix 1  Special Relay List
 
APPENDICES
TableApp.11 Special relay
ACPU 
Special 
Relay
Special 
Relay after 
Conversion
Special 
Relay for 
Modification
Name Meaning Details Corresponding CPU
M9200 SM1200 ----
ZNRD  instruction 
(LRDP instruction 
for ACPU) 
reception (for 
master station)
OFF : Not accepted
ON : Accepted
• Depends on whether or not the  ZNRD  (word device read) 
instruction has been received.
• Used in the program as an interlock for the  ZNRD 
instruction.
• Use the  RST  instruction to reset.
QnA
M9201 SM1201 ----
ZNRD  instruction 
(LRDP instruction 
for ACPU) 
completion (for 
master station)
OFF : Not completed
ON : End
• Depends on whether or not the  ZNRD  (word device read) 
instruction execution is complete.
• Used as a condition contact for resetting M9200 and 
M9201 after the  ZNRD  instruction is complete.
• Use the  RST  instruction to reset.
M9202 SM1202 ----
ZNWR  instruction 
(LWTP instruction 
for ACPU) 
reception (for 
master station)
OFF : Not accepted
ON : Accepted
• Depends on whether or not the  ZNWR  (word device 
write) instruction has been received.
• Used in the program as an interlock for the  ZNWR  
instruction.
• Use the  RST  instruction to reset.
M9203 SM1203 ----
ZNWR  instruction 
(LWTP instruction 
for ACPU) 
completion (for 
master station)
OFF : Not completed
ON : End
• Depends on whether or not the  ZNWR  (word device 
write) instruction execution is complete.
• Used as a condition contact to reset M9202 and M9203 
after the  ZNWR  instruction is complete.
• Use the  RST  instruction to reset.
M9204 SM1204 ----
ZNRD  instruction 
(LRDP instruction 
for ACPU) 
reception (for local 
station)
OFF : Not completed
ON : End
• On indicates that the  ZNRD  instruction is complete at the 
local station.
M9205 SM1205 ----
ZNWR  instruction 
(LWTP instruction 
for ACPU) recep-
tion (for local 
station)
OFF : Not completed
ON : End
• On indicates that the  ZNWR  instruction is complete at the 
local station.
M9206 SM1206 ----
Host station link 
parameter error
OFF : Normal
ON : Abnormal
• Depends on whether or not the link parameter setting of 
the host is valid.
M9207 SM1207 ----
Link parameter 
check results
OFF  : Match
ON  : Mismatch
• Depends on whether or not the link parameter setting of 
the master station in tier two matches that of the master 
station in tier three in a three-tier system.
(Valid for only the master station in a three-tier system.)
M9208 SM1208 ----
Sets master 
station B and W 
transmission range 
(for lower link 
master stations 
only)
OFF : Transmits to tier2 and 
tier 3
ON : Transmits to tier2 only
• Depends on whether or not the B and W data controlled 
by higher-link master station (host station) is sent to lower-
link local stations (tertiary stations).
When SM1208 is OFF............B and W of host station is 
sent to tertiary stations.
When SM1208 is ON..............B and W of host station is 
not sent to tertiary stations.
M9209 SM1209 ----
Link parameter 
check command 
(for lower link 
master stations 
only)
OFF : Executing the check 
function
ON : Check non-execution
• Set to ON not to match B and W of the higher and lower 
links.
• When SM1209 is ON, the link parameters of the higher 
and lower link are not checked.
• When SM1209 is OFF, the link parameters of the higher 
and lower link are checked.
M9210 SM1210 ----
Link card error (for 
master station)
OFF : Normal
ON : Abnormal
Control is performed depending on whether the link card 
hardware is faulty or not.
M9211 SM1211 ----
Link module error 
(for local station 
use)
OFF : Normal
ON : Abnormal
Control is performed depending on whether the link card 
hardware is faulty or not.
M9224 SM1224 ---- Link status
OFF : Online
ON : Offline,station-to-
station test, or self-
loopback test
Depends on whether the master station is online or offline or 
is in station-to-station test or self-loopback test mode.
M9225 SM1225 ---- Forward loop error
OFF : Normal
ON : Abnormal
Depends on the error condition of the forward loop line.
M9226 SM1226 ---- Reverse loop error
OFF : Normal
ON : Abnormal
Depends on the error condition of the reverse loop line.
M9227 SM1227 ---- Loop test status
OFF : Not being executed
ON : Forward or reverse 
loop test execution 
underway
Depends on whether or not the master station is executing a 
forward or a reverse loop test.
M9232 SM1232 ----
Local station 
operation status
OFF : RUN or STEP RUN 
status
ON : STOP or PAUSE 
status
Control is performed depending on whether a local station is 
in the STOP or PAUSE mode.
M9233 SM1233 ----
Local station error 
detect status
OFF : No errors
ON : Error detection
Depends on whether or not a local station has detected an 
error in another station.